Hatchet and pitchfork have additional weirdness that overshadows something new about them: they are weapons you can share with the party.
In mystic and seeker, having a hand weapon is of marginal utility. There are exceptions (like Joe Diamond or Lily), but generally, a spell or attack event makes more sense than a knife.
Hatchet changes that, and more effectively in most cases than pitchfork, which is why this is a review of hatchet instead of pitchfork. (Besides, Pitchfork reviews music.)
Some Arkham scenarios, especially in the Vale, end with a big monster, or monster swarm. Other ones, especially in duo, have extremely variable monster outputs, which means easy sailing until you’re suddenly buried in more enemies than the fighter can handle. I’ve had good luck with Yorick bringing this out, giving Amanda something to fight with, in the turns when he’s not using a chainsaw.
Hatchet is also an amazing combo piece. People have mentioned Beat Cop(2), as a way to recur in the middle of a fight. Long Shot is a separate instance of damage, so it won’t force the discard. For other uses, Rita’s evade (perhaps through a breaking and entering) could recur hatchet. Blood Rite doesn’t provoke attacks of opportunity. And if you want to spend the XP, enchant weapon is an optional trigger, so you can deal two or three damage, then use one of the additional damage dealers listed above.
The last use is marginal, but you might useful: clearing hand slots. Mystics running scroll of secrets might not want to spend the action, or might not have the card to send it back into the trash. Guns run out of ammo, thieves kits run out of supplies. Hatchet solves it!